The goal of this project is to understand how genes are controlled during development. We are studying the Drosophila gene engrailed (en), which is important for proper segmentation of the embryo and also for formation of the adult. The continually evolving pattern of en expression reflects the multiple roles it plays during development. At least 70 kb of regulatory DNA are necessary for regulation of en expression. We are interested in how this complex regulatory region evolved and in its conservation throughout evolution. Towards this end, we are cloning the en gene from mosquito and studying the conservation of coding and non-coding regions between Drosophila and mosquito en DNA. We are using functional tests in an attempt to understand the meaning of the conserved sequences. In previous studies, we found that sequences within a 1 kb en intron contain the information to give en stripes early in development. We are beginning to study this intron in more detail in order to identify proteins which bind to en DNA and regulate en expression. Through these studies we hope to gain more insight into the complex mechanisms which control development.